The First Ever Pesach Seder

HaShem told the Jews to sacrifice the lamb on the afternoon of the 14th day of the month of Nissan, and to spread blood from the lamb on all three sides of the door frame: top, right, and left. (This formed the shape of the Hebrew letter chet, which is the first letter of the word Chai meaning life.)

Then they were told to roast the lambs over fire. The meat had to be cooked until it was "well done" and eaten at night, along with matzah and marror (bitter herbs). They were to eat it in a hurry, with their walking sticks in their hands, and be ready to leave Egypt that very night -- on a moment's notice!